What Really Happens to Your Body When You Skip Breakfast

We've all heard how important it is to eat breakfast in the morning, but many of us find ourselves rushing out the door without whipping out the frying pan or even scarfing down a yogurt. Let’s make one thing very clear: You should never, ever skip breakfast. You've almost definitely heard that advice before (and most likely continued on with your breakfast-less day). But why? Deciding to forgo a morning meal seems like no big deal, but a 2016 study done by the National Institute of Child and Human Development showed that even having two breakfasts is better than none.

“Breakfast serves the same purpose as all other meals—it’s a time to nourish your body and give it important nutrients to keep it healthy and energized,” Nora Minno, a registered dietitian and certified dietitian/nutritionist says. “Skipping breakfast can cause you to fall short on important nutrients like fiber, protein and disease-fighting antioxidants, which can lead to everything from dehydration to serious illnesses. Plus, [breakfast] provides protein, fat and carbs, which are all important for maintaining lean muscle mass!”

Not only that, but what you eat—or don't eat—first thing in the morning affects your diet and body for the rest of the day. According to registered dietitian and personal trainer Maxine C. Yeung, skipping breakfast causes your blood sugar levels to drop, meaning you might start to feel lightheaded, moody, tired, and unable to get your work done. The longer you go without eating, the quicker your blood sugar levels will spike at your next meal. Yeung says that these lows and highs can negatively affect your mood and energy levels, causing crashes and midday slumps. Therefore she suggests eating regularly throughout the day and keep your blood sugar levels at a steady level.

She also notes that not grabbing a bite to eat in the morning can set off starvation alarm bells in your brain, urging you to stock up high-calorie foods as the day goes on, cause you to eat quickly and eat larger portions, which can lead to weight gain—well, possibly. According to Yeung, there are no studies that support this claim entirely, but that there are studies showing that people who eat breakfast have overall better health.

“I typically go by the rule that you want avoid going longer than six hours without eating during the day, because your metabolism will become less efficient trying to preserve your energy at that point,” she says. “The exception to the day is when we sleep, which is why eating within one to two hours after waking up is a good idea to help get your body back to burning calories more efficiently for the day and give you energy to tackle your daily tasks.”

So what should you grab? Minno recommends a balanced breakfast of something like two poached eggs on a bed of steamed spinach, ¼ avocado spread on a slice of sprouted toast and a side of fresh berries. Think: anything containing lean protein, healthy fats, complex carbs, and lots of antioxidants is game. If the thought of a meal in the morning seems overwhelming, Yeung suggests starting with something simple, such as an individual sized plain nonfat or low-fat Greek yogurt with some berries, or a low-fat cheese stick with an apple.

And for all of the caffeine lovers out there, a cup of Joe is no substitute for the real thing. Caffeine can’t sustain your energy the way food filled with complex carbohydrates can leading to the mid-day crash, so reconsider that quick trip to Starbucks (or at least grab a Bistro Box too!). But beware: too much coffee can also dehydrate you, according to Yeung.

“We already know that oftentimes adults mistake hunger for thirst,” she says. “So if you only drink coffee for the first part of the day, you may risk being even thirstier later in the day, but end up overeating as a result.”